Small-angle scattering study of TAC8: A surfactant with cation complexing potential

TAC8 is a new surfactant molecule. Two octyl chains form the hydrophobic part of the molecule whereas the hydrophilic part is made of two glucose groups and a cyclam ring, which gives the molecule a potential for complexing metal ions or compounds. Aqueous solutions of pure TAC8 and of TAC8 with equimolar complexed CuF₂ are studied using small-angle neutron and X-ray scattering. The shape and dimensions of the micelles are determined from the scattering data using two different approaches. The first approach is model independent and uses indirect Fourier transformation of the scattering data followed by square-root deconvolution of the obtained pair-distance distribution function in order to determine the scattering length density profile. In the second approach a molecular constrained model of the micelles is fitted to the X-ray and neutron scattering data simultaneously. The results of these two different approaches agree very well. The analysis shows that both the pure TAC8 and the TAG8 with complexed CuF₂ aggregate into short cylindrical micelles with aggregation numbers of approximately 20. The micelles of TAG8 with CuF2 are quite monodisperse in the concentration range studied, and their effective charge is very low compared to that of typical ionic micelles.